Long-time Hillary Clinton adviser Sidney Blumenthal is set to be interviewed on June 16 by the House committee investigating the 2012 attacks in Benghazi, Libya.

The House Select Committee on Benghazi, in announcing Blumenthal's appearance Friday, said his deposition will be conducted in a closed session without media coverage. The move is part of the panel's investigation of the Sept. 11, 2012 attacks on two U.S. compounds in Benghazi, Libya, that led to the death of four Americans, including U.S. Ambassador Christopher Stevens.

Blumenthal has become a focus of the House Select Committee on Benghazi since revelations he had been sending Clinton what she called "unsolicited" memos about Libya, where he was trying to arrange business deal, while she was secretary of state. Those memos included early suggestions that terrorists were responsible for Benghazi attacks. Blumenthal did not work for the State Department but from 2009 to 2013 was employed full-time by the Clinton Foundation, founded by Clinton's husband, former President Bill Clinton. After 2013, Blumenthal became a consultant.

His correspondence with the former secretary of state, who is now running for president, became public as a result of a batch of e-mails turned over to the committee after revelations that Clinton had been using a private e-mail address and home server to conduct business while she worked for the government.

Congressional Republicans have been trying for more than two years to show that Clinton failed to bolster security before the Benghazi attack and should share blame for the administration's initial, erroneous account that the attacks were not related to terrorism. The Benghazi panel's chairman, Republican Trey Gowdy of South Carolina, has said he plans to issue a final report next year, just months before the presidential election.

Democrats have accused the House Republicans of stringing out its investigation of the Benghazi attacks to undercut Hillary Clinton's campaign.

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